This Saturday, May 30, educators and scientists will host World Fish Migration Day across multiple sites along the lower Hudson River Estuary, spotlighting how estuaries sustain the timed journeys of ocean fish—from Atlantic sturgeon and river herring to glass
By mid-morning on May 30, the Hudson River Estuary will be the stage for a spectacle most people never get to see up close: migratory fish moving through “the long arm of the sea” in a carefully timed rhythm.
World Fish Migration Day—hosted by scientists and educators at multiple locations along the lower Hudson River Estuary—invites the public to join in. The event celebrates the role estuaries play in the life cycle of many ocean fish species that reproduce by moving between the ocean and connected estuaries.
In the estuary, conditions are built for survival. Newly spawned fish find abundant food and shelter. giving them time to grow and mature before they head into deeper ocean waters. The habitat isn’t one thing—it’s a patchwork of marshes. mudflats. and small backwater channels. offering protection from predation and reducing competition for resources. Without those estuarine nurseries, the biodiversity of oceans would suffer greatly.
A small flatfish often caught during these efforts—called a hogchoker—lives in the brackish. slightly salty section of the Hudson. Other species that show up during this time of year underline why people keep coming back to this river for the annual ritual: the movement connects ocean and land. marine and freshwater. in one continuous cycle.
The Hudson is unusually important because it provides some of the most critical spawning habitat along the entire Eastern Seaboard. The Hudson River Estuary stretches 153 miles from where it leaves the ocean until it ends at the Troy dam just past Albany. Its long configuration traces back to geology: it is a fjord carved by meltwater from ice during the last ice age. Along the way. the water transitions from deep marine saltwater to shallower brackish areas and then to freshwater as it links to tidal wetlands.
That sweeping gradient supports multiple young-of-the-year fish—those hatched during the calendar year—and multiple migratory species, from the small hogchoker to the feisty blue crab.
For anadromous fish—species born in freshwater—the challenge is bigger. They must move from the ocean to freshwater to spawn and then return, adjusting physiology and morphology as conditions shift. Hudson iconic migratory species include river herring, American shad, striped bass, and the federally endangered Atlantic sturgeon.
Atlantic sturgeon enter the river at this time of year to spawn. heading into the freshwater section of the upper estuary. Their timing is triggered by changing water temperatures in spring. In earlier generations. these “river runs” drew fishermen who cast out nets for the annual shad run. harvested Atlantic sturgeon. and pulled in striped bass by the dozens. While those days may be gone, the Hudson still hosts a critical annual spawning ritual.
The estuary also plays host to a different kind of migration. Catadromous species spend most of their adulthood in freshwater, but they migrate to the ocean to spawn. The American eel is one such reverse migrator: it spends its entire life in freshwater before moving thousands of miles into the ocean to spawn and die. releasing its small planktonic embryo into currents that carry it back toward natal rivers.
At this time of year, the celebration includes the arrival of thousands of tiny year-old glass eels migrating into the Hudson and moving up into Hudson tributaries. There, they spend the next few decades before returning to the Sargasso Sea when reproductive instinct pulls them back.
What might people see during the day? The event is designed for exactly that question.
World Fish Migration Day runs globally from late May into early June and focuses attention on how important estuaries and rivers are worldwide. Over the past decade. Lamont-Doherty Earth Observatory—which is part of the Columbia Climate School—has coordinated with the NYS Department of Environmental Conservation and the Hudson River National Estuarine Research Reserve. working alongside multiple environmental organizations to host a local event for the Hudson Estuary.
During that time. the effort has netted 9. 676 fish from 50 different species from the broader 235 species identified in the mainstem Hudson River Estuary by New York State researchers. For a single-day event in just the lower part of the estuary. those numbers are part of what keeps attendees coming back.
Some of the most abundant catches are small feeder fish that have recently spawned. including the silvery Atlantic silverside and bay anchovy. Other strong numbers include mummichog. a small killifish whose males sport a bright yellow belly during mating season. and Atlantic menhaden. which spawn just outside the mouth of the Hudson before the young of year move into the Hudson to feed and use its shelter.
Attendees also get the kind of surprises that turn a science activity into a memory. Over the years, catches have included lined seahorse and northern stargazers—species that can thrill people just by being seen at all.
For anyone who wants to review the full history of finds, there is a check link mentioned for the full range of what has been caught over the years.
On the day itself, the “World Fish Migration Lower Hudson & Harbor Fish Count” is built around public participation. The event includes public fishing events where participants can help pull a seine net to glimpse iconic species—or simply cheer and assist with fish identification using simple tools provided.
Lamont will host an event at its Hudson River Field Station at 200 Ferry Rd, Piermont NY, from 12 to 4 p.m. Other sites are distributed throughout the lower Hudson and NYC area. meaning people don’t have to travel far to join in the annual ritual. Full details about the specific places and times for events are available via the event website.
Directors and coordinators tied to the education work also help set the tone for what the day is about. Margie Turrin is director of educational field programs at Lamont-Doherty Earth Observatory and director of the Hudson River Field Station; she develops and runs projects focused on community engagement and understanding Earth and environment.
Marisa Annunziato is education and outreach coordinator at Lamont, where she organizes and runs science education projects for all ages. She holds a marine science degree and enjoys connecting the public to the Hudson River through education and community science programs.
On May 30, it won’t just be a celebration of wildlife. It will be a chance to witness, in real time and with your hands on the seine net—or your eyes on what the net brings up—how the Hudson’s estuary habitats keep the migratory cycle going.
World Fish Migration Day Hudson River Estuary Atlantic sturgeon river herring American shad striped bass American eel glass eel seine net Lamont-Doherty Earth Observatory Hudson River Field Station
Fish migrations are so cool but will it be like… crowded?
So are they like bringing the sturgeon in for people to see or is it just a talk? I feel like “witness” sounds like you’ll actually see a bunch of fish but idk.
I don’t get it, if it’s timed migrations then why would anyone need educators and scientists, like the fish will show up anyway right? Also I thought Hudson fish were basically gone forever after all the pollution. Maybe I’m mixing stuff up.
May 30 sounds nice but the article makes it sound like “the long arm of the sea” is somewhere specific and then it’s multiple sites along the lower Hudson. Like where do you even park? And are they talking about glass eels or glass By some typo? Either way I hope they keep people off the mudflats because people don’t listen.